The various embodiments described herein pertain generally to an ionic elastomer-based capacitor type tactile sensor and a method of manufacturing the same.
Recently, with the rapid development of electronic data devices, mobile data communication devices and mobile smart devices have rapidly propagated. Next-generation electronic systems are expected to be developed to the extent that they can be attached to or inserted into a human body beyond just being mobile. Particularly, an artificial electronic skin or a tactile sensor capable of being bent, extended and attached to a skin or a body of a person or a flexure such as a joint is attracting attention.
Meanwhile, the tactile sensor is classified into two types: one using a resistance variation according to a deformation (piezo resistance effect) and the other using an electrostatic capacitance variation according to a variation in a gap between electrodes due to an external mechanical pressure. In general, the tactile sensor is manufactured through a silicon semiconductor process. Through the silicon semiconductor process, a micro channel can be formed and a high spatial resolution can be achieved. Further, performance of a sensor manufactured through this silicon semiconductor process is relatively high. Besides, if a well-established semiconductor CMOS technology is used together, a complicate signal processing problem can be solved by embedding a capacitor, a decoder, or the like in the tactile sensor. Despite these advantages, since a silicon material has low durability and is not flexible, attaching a silicon sensor to a curved surface has been impossible.
To solve the aforementioned problem, many active researches have been conducted to improve durability of the tactile sensor by using various materials and to develop a material capable of sensing even a very fine pressure/strain. Development of such a material is regarded as a core technology having a wide range of applications to various fields such as artificial electronic skins, tactile sensors, artificial prostheses, robotics, medical devices, and so forth.
In this regard, International Patent Publication No. WO2013/044226 (entitled “Artificial skin and elastic strain sensor”) describes a technique using an elastic strain sensor which is equipped with an electrode and an elastic member having at least two channels and a strain axis to detect and trace a motion of a support structure. In this technique, the elastic strain sensor is configured to detect an electric resistance which is changed as cross sections of the channels are changed when a pressure is applied to the elastic member.
Since, however, such an artificial skin measures only a deformation of the elastic member caused by an external mechanical pressure, the electric resistance can only be detected sensitively within a limited pressure range. In order to detect all pressure ranges, different device structures need to be used for the individual pressure ranges. Thus, there has been a limit in achieving high integration of devices.